OK so I'm 16 and sexually active.. I have normal periods just like any other person does.. well on may 30 I had what I guess you could call "sex" (yes it was PROTECTED) and I hadn't had sex in almost a year so it hurt a little so my boyfriend pulled out really quick and then came(not inside me ither) he also told me that there was nothing wrong with the condom, but about a day or two after I got what I'm almost 100% positive is my period- the only thing I'm worried about is that its brown with a mixture of blood and even a little bit of clots.. so I guess old blood and new blood(brown and red) and after the shower or after I use the bathroom its red. Also I am on iron vitamins for bloody noses to help reduce them so I'm pretty sure that could throw my period off a bit. So what I'm trying to ask is- is this my period or should I be worried I'm pregnant? Cause I read online and everythings like pregnancy related so I'm worrying myself half to death and not sleeping. I have no clue what to do or if this is my period or what. So yeaa help me out :(
Thanks in advanced.

Oh and at times this was all heavy enough to use a tampon not completely fill it but enough was on it.

I've never heard of iron pills throwing off your period, I don't see why a supplement like that would cause it. The old and new blood would make sense. Usually the little clot things are basically the old egg and stuff from your uterus (I believe. I'm sure someone will correct me if I'm wrong). Unless they're larger than normal for you, I wouldn't be concerned over them. From what you've told us, I see no reason to lean towards thinking you are pregnant. But the only way to be sure is to take a pregnancy test.